FIELD OF THE INVENTION
The present invention relates to a method for detecting impermissible operating states in electronically controlled tumble dryers, in particular the state of motion of the laundry drum. During a drying operation, laundry is moved in a laundry drum having electrodes. The electrical conductivity of the laundry is periodically measured as a result of contact occurring at least from time to time between the laundry and the electrodes of the laundry drum.
In tumble dryers, laundry is put into a drum, the drum is set into motion and heated air is moved through the drum, whereby moisture is removed from the laundry and the laundry is thus dried.
During the drying operation, it is possible for critical states to occur if, for example, the drive for the laundry drum has a fault, which is the case, for example, in the event that the drive belt of the laundry drum breaks. As a result of which the normal drying operation cannot be completed.
The occurrence of the fault is not detected by a temperature measurement of the tumble dryer, since the normal quantity of process air continues to flow around all the temperature regulators, in which the temperature regulators are set to and registering normal operating temperatures.
In order to detect the fault of a stalled drum and, if appropriate, to abort the drying operation, various solutions have been proposed.
In one of the solutions known from the prior art, the torn belt is detected via end-position switches, but this disadvantageously requires an additional outlay for components and corresponding control devices.
In another proposed solution, the rotary motion of the drum is registered by optoelectronic components, which once again necessitates an additional outlay for components, and the corresponding electronic control devices.